Iterative Reconstruction for Head CT: Effects on Radiation Dose and Image Quality

Area of Science:

• Radiology
• Medical Imaging
• Computed Tomography

Background:

• Iterative reconstruction techniques in CT aim to lower radiation dose while maintaining or improving image quality.
• Conventional filtered back-projection (FBP) is a standard reconstruction method.

Purpose of the Study:

• To evaluate the impact of sinogram-affirmed iterative reconstruction (SAFIRE) on radiation dose and image quality for noncontrast adult head CT.
• To compare SAFIRE with FBP reconstruction.

Main Methods:

• Retrospective analysis of 107 adult head CT scans reconstructed using SAFIRE and/or FBP.
• Quantitative assessment of radiation dose, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR).
• Qualitative assessment of image noise, artifacts, gray-white matter differentiation, small structure visibility, and sharpness by two independent readers.

Main Results:

• Mean effective radiation dose was reduced by 15% with SAFIRE (2.0 to 1.7 mSv).
• SAFIRE significantly improved gray matter SNR, white matter SNR, and GM-WM CNR.
• Reduced image noise and artifacts, with enhanced GM-WM differentiation, small structure visibility, and sharpness were observed with SAFIRE.

Conclusions:

• SAFIRE effectively reduces radiation dose in noncontrast adult head CT.
• SAFIRE significantly enhances multiple quantitative and qualitative aspects of image quality compared to FBP.